U.S. patent number 4,854,769 [Application Number 07/155,905] was granted by the patent office on 1989-08-08 for system for paving inclined and/or curved surfaces.
This patent grant is currently assigned to Kajima Corporation, Kasima Road Company. Invention is credited to Kazumitsu Asai, Mitsuo Fukukawa, Kouhei Mio, Yoshiharu Okamoto, Masayuki Yazawa.
United States Patent |
4,854,769 |
Fukukawa , et al. |
August 8, 1989 |
System for paving inclined and/or curved surfaces
Abstract
An inclined roadbed is paved by vehicles which are connected by
wires to uphill anchor vehicles. A paving vehicle on the inclined
surface has a device for projecting a laser beam to a
beam-receiving device on its respective anchor vehicle. The height
of the wire connection point on the anchor vehicle is changed in
response to signals from the beam-receiving device, so as to
equalize the forces exerted on the inclined surface by the left and
right sides of the paving vehicle. For paving surfaces such as
automobile test tracks which have compound curvatures, a pavement
laying apparatus has a curved surface formed by a plurality of
interconnected screed plates which are each connected to a
respective screw jack. A microcomputer stores data representing the
desired shape of the pavement at different points along the travel
path of the apparatus. Signals representing the travel distance of
the apparatus are sent to the microcomputer, and the microcomputer
sends output signals which control the jacks to produce a pavement
surface which has the desired shape.
Inventors: |
Fukukawa; Mitsuo (Saitama,
JP), Yazawa; Masayuki (Chiba, JP), Asai;
Kazumitsu (Saitama, JP), Okamoto; Yoshiharu
(Saitama, JP), Mio; Kouhei (Kanagawa, JP) |
Assignee: |
Kajima Corporation (Tokyo,
JP)
Kasima Road Company (Koji, JP)
|
Family
ID: |
26364214 |
Appl.
No.: |
07/155,905 |
Filed: |
February 16, 1988 |
Foreign Application Priority Data
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Feb 26, 1987 [JP] |
|
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62-41500 |
Feb 26, 1987 [JP] |
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62-26428[U] |
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Current U.S.
Class: |
404/72; 404/96;
404/84.8; 404/118 |
Current CPC
Class: |
E01C
19/004 (20130101); E01C 19/42 (20130101); E01C
19/48 (20130101) |
Current International
Class: |
E01C
19/00 (20060101); E01C 19/48 (20060101); E01C
19/22 (20060101); E01C 19/42 (20060101); E01C
019/00 (); E01C 019/22 (); E01C 023/07 () |
Field of
Search: |
;404/84,96,101,104,118-120,72,75 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Bui; Thuy M.
Assistant Examiner: Letchford; John F.
Attorney, Agent or Firm: Beveridge, DeGrandi &
Weilacher
Claims
We claim:
1. A method for paving a three-dimensional curved surface with a
crawler truck which is associated with a travel distance measuring
means for providing distance-indicating output signals which are
indicative of the position of the crawler truck along its path of
travel, pavement laying means attached to the crawler truck for
uniformly laying a paving material,
said pavement laying means having a surface which is curved in a
vertical plane tranverse to said path of travel and a plurality of
jacks which are vertically movable, transversely pivotable, and are
operable to adjust the shape of the curved surface, and a
microcomputer means provided with stored curved surface shape data
which correspond to measuring points along the travel path of the
pavement laying means,
said method including the steps of receiving, at said microcomputer
means, said output signals from the travel distance measuring
means; generating computer output signals based on said curved
surface shape data; and, controlling the jacks based on said
computer output signals to change the curvature of said curved
surface.
2. A method according to claim 1, wherein the curved surface is
formed by a plurality of screed plates,
said screed plates being movable relative to each other, link means
which connect the screed plates to the jacks, each of said link
means including a bracket and arms, each said bracket being
pivotally connected to an actuator, and each of said arms is
pivotally connected to the bracket and a screed plate.
3. A method according to claim 1, wherein a screw spreader means is
mounted forwardly of the curved surface for spreading a paving
material laterally, said screw spreader means including at least
two screws which are moved vertically by automatic control.
4. A method according to claim 3, wherein the curved surface is
formed by a plurality of screed plates,
said screed plates being movable relative to each other, link means
which connect the screed plates to the jacks, each of said link
means including a bracket and arms, each said bracket being
pivotally connected to an actuator, and each of said arms is
pivotally connected to the bracket and a screed plate.
5. A system for paving a three dimensional curved surface
comprising a crawler truck, a travel distance measuring means for
providing output signals indicating the position of the crawler
truck along its path of travel, and pavement laying means attached
to the crawler truck for uniformly laying a paving material,
said pavement laying means having a surface which is curved in a
vertical plane traverse to said path of travel, and a plurality of
jacks which are vertically movable, transversely pivotable, and are
operable to adjust the shape of the curved surface,
a microcomputer means provided with stored curved surface shape
data which correspond to measuring points along the travel path of
the pavement laying means,
said microcomputer means receiving said output signals from the
travel distance measuring means,
said microcomputer means also generating computer output signals
which control the jacks based on said stored curved surface shape
data to change the curvature of said curved surface.
6. A system according to claim 5 having a plurality of screed
plates which together form said curved surface,
said screed plates being connected to each other by joints so as to
be movable relative to each other, and links which connect the
screed plates to the jacks.
7. A system according to claims 6 wherein said jacks are screw type
jacks.
8. A system according to claim 5, wherein the curved surface is
formed by a plurality of screed plates,
said screed plates being movable relative to each other, link means
which connect the screed plates to the jacks, each of said link
means including a bracket and arms, each said bracket being
pivotally connected to an actuator, and each of said arms is
pivotally connected to the bracket and a screed plate.
9. A system according to claim 5 wherein a screw spreader means is
mounted forwardly of the curved surface for spreading a paving
material laterally, said screw spreader means including at least
two screws which are moved vertically by automatic control.
10. A system according to claim 9, wherein the curved surface is
formed by a plurality of screed plates,
said screed plates being movable relative to each other, link means
which connect the screed plates to the jacks, each of said link
means including a bracket and arms, each said bracket being
pivotally connected to an actuator, and each of said arms is
pivotally connected to the bracket and a screed plate.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for
supporting a paving vehicle on an inclined surface. Asphalt
finishers, steel rollers and tire rollers are all typical paving
vehicles.
Also, the invention relates to a method and apparatus for paving a
three-dimensional curved surface and, more particularly, to a
system for uniformly laying a paving material such as asphalt onto
the three-dimensional curved surface.
A slope face such as a test course for automobiles is paved by
laying asphalt on the slope face with an asphalt finisher and then
compacting the asphalt with a steel roller, tire roller, or the
like. These steps are well known. For example, as shown in FIG. 1,
an asphalt finisher C, a steel roller D, and a tire roller E, are
supported by wires W from anchor vehicles B which run on a top end
portion A. The asphalt finisher C, steel roller D, and the tire
roller E run on the slope face F, thereby paving the surface of the
inclined slope face. In the diagram, T denotes a dump truck and R
indicates a machine for laterally transporting a paving material
such as asphalt or concrete.
When paving machines on an inclined surface are supported by wires,
an improper supporting method can result in nonuniformity of the
paved surface and a deterioration of its working quality. However,
hitherto, a satisfactory countermeasure has not been realized. For
example, FIG. 2, illustrates the case where a paving machine M is
supported on the inclined surface F by the wire W from an anchor
vehicle B. A fixed point P of the wire is offset by a distance l
from the position of the center of gravity G of the paving machine
M, so the paving machine is subjected to a moment M=T.multidot.l
which generates uneven loads in the wheels H and adversely
influences the finished state of the paved roadbed.
On the other hand, as shown in FIG. 3, when the fixed point P of
the wire is located on the extension line of the center of gravity
G, no problem will be caused if an angle .theta. between the
supporting direction of the wire W and the inclined surface F
coincides with this direction. However, if the supporting angle of
the wire increased by an angle .alpha. greater than the angle
.theta. during running, the component of force J=T sin .alpha.
occurs. The loads of the right and left wheels H of the paving
machine M are unbalanced. The wheel with a smaller load can slip
and the paved surface becomes rough. In the worst case, the paving
apparatus M cannot run. The working efficiency deteriorates and the
paving quality deteriorates.
In levees and similar structures, where the angle of inclination of
the inclined surface is constant, the problems of unbalanced wheel
loads can be avoided by presetting the supporting direction of the
wire. However, as shown in FIG. 4, when the slope face F is curved
as in an automotive test course, the inclination continually
changes in directions which are transverse and longitudinal of the
test course. Accordingly, the foregoing problems will occur if some
countermeasures are not taken.
Asphalt finishers for finshing curved roadbed surfaces have been
disclosed in the Official Gazette of Japanese patent publication
No. 38530/78 and the Official Gazette of Japanese utility model
laid-open publication No. 85105/80. However, these prior devices
have shortcomings in the respect that manual operation is needed to
pave surfaces which have complicated curvatures. This requires
skilled and experienced operators in order to achieve the desired
degree of accuracy.
It is an object of the present invention to provide an apparatus
for supporting a paving machine which avoids the foregoing
problems, even when the inclination angle of the slope face
changes, as is the case in an automative test course.
It is also an object of the invention to provide a system for
paving a three-dimensional curved surface which can provide high
accuracy without manual operation.
SUMMARY OF THE INVENTION
In one respect, the invention pertains to a method and apparatus
involving an anchor vehicle which supports a paving vehicle on an
inclined surface by means of a wire. The paving vehicle has a light
projecting apparatus which directs a beam of light, preferably a
laser beam, at a beam-receiving means located on the anchor
vehicle. One of the vehicles, preferably the anchor vehicle, has
means for adjusting the height of the wire extending therefrom, and
this height adjustment means is moved vertically when the position
of the light beam received by the beam-receiving means deviates
from a preset position. By virtue of this arrangement, the forces
exerted by the paving vehicle on the inclined surface are equal for
the left and right sides of the vehicles.
Another feature of the invention involves the construction and
operation of a pavement laying means on a movable crawler truck.
The pavement laying means has a curved surface and a plurality of
jacks which are vertically movable in order to adjust the shape of
the curved surface. A microcomputer has stored curved surface shape
data which correspond to the desired shape at measuring points
along the travel path of the pavement laying means. A travel
distance measuring device on the crawler truck sends signals to the
microcomputer which, upon receiving such signals, generates output
signals which control the jacks based on the stored curved surface
shape data. Preferably, the curved surface is formed by a plurality
of screed plates which are connected together by joints; and, links
are provided to connect the screed plates to the jacks. Also, it is
preferred that the jacks be of the screw type.
For a more complete description of a preferred embodiment of the
invention, reference is made to the accompanying drawings and the
detailed description which appears below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cutaway perspective view showing an existing system for
paving an inclined surface to which the invention is
applicable.
FIGS. 2, 3 and 4 are diagrammatic elevational views showing
conventional means for supporting paving machines on sloped
surfaces.
FIG. 5 is a diagrammatic elevational view showing one embodiment of
the invention.
FIG. 6 is a front view of a portion of the apparatus shown in FIG.
5.
FIG. 7 is a view of a light receiving device used in the embodiment
of FIG. 5.
FIG. 8 is a flowchart showing the operation of the control means in
the FIG. 5 embodiment.
FIG. 9 is a side elevational view of a second embodiment of the
invention.
FIG. 10 is a rear view of the FIG. 9 embodiment.
FIG. 11 is an enlarged front view of one side of a screw spreader
used in connection with the second embodiment of the invention, the
other side being a mirror image thereof.
FIG. 12 is an enlarged rear view of a pavement laying apparatus
used in connection with the embodiment of FIGS. 9-14.
FIG. 13 is a rear view showing in diagrammatic fashion the means
for controlling the shape of the FIG. 12 apparatus.
FIG. 14 is a flow chart showing the operation of a microcomputer
used in the embodiment of FIGS. 9-14.
DETAILED DESCRIPTION
A first embodiment of the invention is shown in FIGS. 5-7.
Referring first to FIGS. 5 and 6, it will be seen that two wires
extend from the anchor vehicle B to the inclined paving machine M
on the slope face F. The anchor vehicle B travels longitudinally
along the uphill side A of the slope face.
The paving machine B in FIG. 5 is similar to the machine shown in
FIGS. 2-4. It has a main body which is supported by wheels H and
wires W, the latter being fixed at the points P which are aligned
with the center of gravity G. Therefore, when the wires W lie in
the same direction as the inclination angle .theta., almost equal
loads act on the right and left wheels H. A light projector 130 on
the paving machine M emits a laser beam which is angularly
adjustable so that it can be directed almost perpendicular to the
line GL which is perpendicular to the slope face F and passes
through the center of gravity G of the paving machine M.
The main body of the anchor vehicle B has independently steerable
crawlers 103 and a main frame 101 mounted on the crawlers. A
driver's cab 102, a wire feeding apparatus, a hydraulic pressure
generator and other components are mounted on the frame 101. The
wire feeding apparatus includes a winch 109 which feeds out or
takes up the wire, a pair of arms 107 which are spaced apart and
are pivotally mounted on fulcrums 120, guide sheaves 104 which are
rotatably mounted on the arms 107, guide sheaves 105 which are
rotatably attached to the fulcrums 120, and hydraulic
piston-cylinder units 110 which are operable to adjust the angles
and heights of the arms 107. The wires W from the winch 109 are
wound around the guide sheaves 104 and 105, and they are connected
to the paving machine M. The arms 107, guide sheaves 104 and units
110 provide a height adjusting means.
As shown in FIG. 6, the swinging ends of the arms 107 are connected
together by a member 106. Therefore, only one hydraulic cylinder
unit is required to move both arms synchronously, and only one
winch 109 is provided.
A light receiving device 131 which receives the laser beam can be a
conventional photosensitive cell which is attached at or near the
center of the member 106. As shown in FIG. 5, the light receiving
angle of the device 131 can be adjusted in order to receive the
laser beam L at a right angle. In lieu of a single diode
photosensitive device, it is also possible to use a light receiver
131a as shown in FIG. 7. In this device, point "0" is the preset
position for receiving the laser beam. When the beam is received at
point "+1" or "-1", the angle of inclination is changed upwardly or
downwardly from one degree from the set point. In this case,
therefore, the hydraulic piston-cylinder units 110 are driven by
only "+1" or "-1" degree to change the inclination angles of the
arms 107, thereby adjusting the feed-out heights of the wires.
These heights can also be adjusted digitally or in an analog manner
as described above. In any case, when the light receiving position
of the device 131 or 131a deviates from the preset position, the
control means generates a signal indicative of the deviation and
sends it to the hydraulic unit 110 to extend or contract the
unit.
The operation of the foregoing embodiment will now be explained in
connection with FIG. 8. First, the cylinder unit 110 is manually
operated to adjust the angle .theta. of the wire W until the angle
between the wire W and the center of gravity line GL of the paving
machine is substantially a right angle as shown in FIG. 5. The
light receiving device 131a is adjusted so that laser beam L is
received at the preset position, point "0". Next, the automatic
operating switch is turned on (step S1). The anchor vehicle B and
paving machine M are driven along the inclined surface, and a check
is made to confirm that the angle of the paving machine, i.e., the
angle of the laser beam, is at the set positional angle during the
paving work (step S2). If the laser beam has deviated from the
preset position, the control means determines the direction of
deviation (step S3), and it sends a single indicative of the
deviating direction to the cylinder unit 110 (step S4 and S5). The
unit 110 is extended or contracted in response to this signal,
thereby holding the wire feed-out height and the angle .theta. at a
set value.
The second embodiment of the present invention is illustrated in
FIGS. 9-14. FIGS. 9 and 10 show a crawler truck or a tractor 201
which carries a hopper 202 for a paving material such as asphalt or
the like. A screw spreader 203 for the paving material is disposed
behind the tractor 201, and an apparatus 204 for uniformly laying
the paving material is disposed behind the screw spreader 203. In
front of the tractor 201, there is a rotatable travel distance
measuring wheel 205 which rides in contact with the surface to be
paved. A signel indicative of the rotational speed or displacement
of the wheel 205 is input into a microcomputer 206 which calculates
the travel distance.
Each side of the screw spreader 203 has two screws 231 and 231'0
which are serially arranged and coupled together by a universal
joint 232. A sprocket 233 is fixed to the end of the screw shaft
near the longitudinal central plane CP of the apparatus. The
machine has a bracket 234 which carries a motor 235 for driving a
chain 236 which is connected to the screwdriving sprocket 233. The
motor 235 is reversible and its speed can be continuously
changed.
The screws 231 and 231', the hydraulic motor 235 and other related
components are all carried by the bracket 234. This bracket is
vertically movable on a slide plate 237 by means of a first
piston-cylinder unit 238. Such movement adjusts the height of the
screws 231 and 231' from the roadbed surface. A second
piston-cylinder unit 238' is also attached to the tractor 201 and
is coupled with a swinging bracket 239 which rotatably supports the
outboard screw portion. Therefore, by actuating the piston-cylinder
unit 238', the angle of the outboard screw portion 231' relative to
the ground is changed. Thus, the screw can change to conform
approximately to the shape of the curved surface to be paved.
The laying apparatus 204 is shown in FIG. 12 where it will be seen
that it has a main beam 241 coupled with the tractor, a plurality
of screw jacks 243 which are pivotally attached to the beam 241 by
pins 242, and a plurality of screed plates 244 attached to the
screw jacks.
Each screed plate 244 is made of a rectilinear member which has a
length of about 40 to 60 cm. The screed plates are coupled together
by ball joints 245. Arms 246 are connected to the screed plates 244
by pins 247; and, the upper ends of these arms 246 are connected by
pins 249 to the ends of brackets 248. Each bracket 248 is connected
by a pin 252 to the end of the screw jack 243. Therefore, the arms
246, brackets 248 and screed plates 244 constitute a type of link
mechanism. By vertically moving the jacks 243, the screed plates
244 form a pseudo curved surface shape.
As shown in FIG. 13, a microcomputer 206 provides signals which
control the formation of the curved screed surface. The curvature
designed for the slope face at any predetermined point is stored in
the microcomputer 206. The travel distance determined by the
measuring wheel 205 shown in FIG. 6 is input to the microcomputer.
When the travel distance increment becomes two meters or any other
selected distance, signals indicative of the desired curvature at
the screed position are output from the microcomputer 206 to motors
250 which extend or contact the screw jacks 243. The extension or
contraction distance of each screw jack 243 is detected by a rotary
encoder 251 and fed back to the microcomputer. This amount is
automatically set into a command value x which has previously been
stored. In this manner, the shapes of the cross sections to be
paved are sequentially accurately formed in the screed every two
meters along its travel.
Even when the command signals are generated every two meters, the
screw jacks slowly extend or contract while the tractor advances.
Therefore, the cross sectional shape of the surface to be paved is
continuously smoothly formed without a stepwise change.
During operation of the embodiment of FIGS. 9-14, a paving material
such as asphalt or the like is placed in the hopper 202 and is
deposited in proper quantities on the slope face by a feeder or the
like. The paving material is tranversely spread by the screw
spreader 203 by the screws 231 and 231' which are rotated by the
motor 235. Simultaneously, the tractor 201 is steered and the
paving material is uniformly laid onto the slope face by the
apparatus 204. To lay the material uniformly, it is important to
control the shape of the screed formed by plates 244 in response to
signals from the microcomputer 206.
The operation of the microcomputer 206 is shown in the flow chart
of FIG. 14. The paving work is started from a predetermined
position (step S11). The microcomputer receives the data indicative
of the rotational speed or displacement of the measuring wheel 205,
and it calculates the travel distance (step S12). A check is made
to determine if the travel distance, i.e., the distance of the
machine along the roadbed, has reached a set incremental value such
as two meters (step S13). If NO, the processing routine is returned
to Step S12. If YES, the curvature data which has previously been
stored in the computer is read out (step S14). This data is also
simultaneously supplied to the motors 250 to drive the screw jack
243. The expansion or contraction distance of each jack 243 is
compared with a set value on the basis of the output data (step
S15). The motors 250 are driven so that the expanding or
contracting amount of each jack 243 is equal to the set value,
thereby moving the jack 243 up or down as appropriate (step S16 or
S17). The jack is driven until it reaches a set value and a check
is made to see if it has reached the set value or not (step S18).
If the jack has reached the set value (YES in Step 18), the control
of the jack and the setting of the screed plate is complete (step
S19). By repeating the foregoing operation at each incremental
distance of two meters, the paving work is completed (step
S20).
Persons who are familiar with the field of the invention will
recognize that it is susceptible to numerous modifications and
variations which differ considerably from the disclosed embodiment.
Therefore, it is emphasized that the invention is not limited only
to the disclosed embodiments but is embracing of modifications and
improvements which fall within the spirit of the following
claims.
* * * * *